package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    @Override
    public Result queryHotBlob(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        //records.forEach(this::queryBlogUser);
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    //根据blob的id查询blob信息
    @Override
    public Result queryBlogById(Long id) {
        //查询blob
        Blog blog = getById(id);
        if (blog==null) {
            return Result.fail("笔记不存在！");
        }
        //查询blob关联用户
        queryBlogUser(blog);

        //查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }


    //封装一个函数用来给blog添加用户信息
    private void queryBlogUser(Blog blog){
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    //判断该笔记有没有点过赞
    private void isBlogLiked(Blog blog){
        //获取登陆用户
        //首页没登陆的话不应该查看是否点赞过
        UserDTO user = UserHolder.getUser();
        if (user == null) {
            //用户未登录
            return;
        }
        Long userId = UserHolder.getUser().getId();
        //判断当前用户是否点赞过
        String key = BLOG_LIKED_KEY + blog.getId();
        //Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
        //点赞排行榜 -- 修改为sortedSet
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }


    //用户点赞功能
    @Override
    public Result likeBlog(Long id) {
        //获取登陆用户
        Long userId = UserHolder.getUser().getId();
        //判断当前用户是否点赞过
        String key = BLOG_LIKED_KEY + id;
        //Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
        //点赞排行榜功能  --> 判断是否存在
        Double score = stringRedisTemplate.opsForZSet().score(key,userId.toString());
        if (score == null) {
            //3如果未点赞 可以点赞
            //3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            //3.2 保存用户到Redis的set集合
            if (isSuccess) {
                //更新成功
                //stringRedisTemplate.opsForSet().add(key,userId.toString());
                //改存入sortedSet 用于实现点赞排行榜功能 zadd key value score
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //4 已经点赞
            //4.1 数据库点赞数 -1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //4.2 把用户从Redis的set集合移除
            if (isSuccess) {
                //更新成功
                //stringRedisTemplate.opsForSet().remove(key,userId.toString());
                //点赞排行榜功能  --> 改sortedSet中删除
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    //实现点赞排行榜展示
    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        //1.查询top5的点赞用户  zrange key 0 4  查到的是zset中根据分数升序的用户id
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        //2.解析出用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        //3.根据用户id查询用户
        Stream<UserDTO> userDto = userService
                .query().in("id",ids).last("order by FIELD(id,"+idStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class));
        //4.返回
        return Result.ok(userDto);
    }


    //保存笔记基础上添加推送关注功能
    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSuccess = save(blog);
        if (!isSuccess) {
            return Result.fail("新增笔记失败！");
        }
        //1查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //2.推送笔记id给所有粉丝
        for (Follow follow : follows) {
            //2.1获取粉丝id
            Long userId = follow.getUserId();
            //2.2推送
            String key = FEED_KEY+ userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    //滚动翻页查询
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前用户 （key）
        Long userId = UserHolder.getUser().getId();
        //查询收件箱 zRevRangeByScore key Max min ITHSCORES limit offset count
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //非空判断
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }
        //解析数据，blogId  score(时间戳)  offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            // 获取id
            ids.add(Long.valueOf(tuple.getValue()));
            // 获取时间戳
            long time = tuple.getScore().longValue();
            if (time == minTime){
                os++;
            }else{
                //说明不是最小值
                minTime = time;
                os = 1;
            }
        }
        //根据blogId查询blog    listByIds(ids)基于mysql的in查询 会造成顺序错乱
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids)
                .last("ORDER BY FIELD(id," + idStr + ")").list();

        //要给每个blog添加完整信息
        for (Blog blog : blogs) {
            //查询blob关联用户
            queryBlogUser(blog);
            //查询blog是否被点赞
            isBlogLiked(blog);
        }

        //封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setMinTime(minTime);
        r.setOffset(os);
        return Result.ok(r);
    }
}
